The car of an elevator is usually suspended by means of roping or belting e.g. on a counterweight via a pulley assembly fixed to the roof of the elevator. Elongation of the roping or belting in a loading situation of the car of the elevator depends in this case on how far the car of the elevator is from the suspension pulley assembly. Elongation of the roping or belting in a loading situation is generally at its greatest when the distance of the car of the elevator from the suspension pulley assembly is at its greatest.
In practice this is because when the car of the elevator is at one of the lowermost floors of the building in which it is located—such as e.g. when the car of the elevator is at the basement floor, from which most of the passengers or load of the elevator come into the car—the elongation of the roping or belting is at its greatest in a loading situation.
It is not uncommon for elevator passengers to experience the elongation of the roping or belting in a loading situation as unpleasant, because in fact the car of the elevator displaces downwards from below the feet as the load of the car increases, whereas the expectation of a passenger would be for the car of the elevator to remain in its position.
Elastic elongation of the roping or the belting affects the sill height of an elevator car at a floor level. The ideal is that there is no sill between the floor level and the floor of the elevator car, and it is to be hoped that such a sill is not disturbing. When the elevator car is loaded, the roping tries to elongate and the floor of the elevator car sinks downwards, in which case a tripping hazard or other impediment can occur, e.g. the transfer of a wheelchair or a child's pushchair into the elevator car or out of the elevator car can become more difficult. The elongation differences of the roping caused by the loading at any given time of the elevator car might affect the accuracy of a run to a floor. Conventionally, the elevator car of a modern elevator is kept accurately at the level with the accurate leveling function of the moving machine. In this case, however, the brakes of the elevator must be kept open.